How to Plumb in an Outdoor Wood Furnace

Determine the type of heating system you have now: forced air or heated liquid (water or oil). Having purchased the correct type of furnace for your heating type, disconnect your old furnace from the ductwork or plumbing.

Set your outdoor furnace up in the appropriate location on your property and dig a trench from your furnace to your house. You will be laying the plumbing or ductwork in here, so make sure it is the appropriate depth and width.

Connect ductwork or plumbing to the furnace and make sure all of your junctions are tight. Run the ductwork or plumbing from your furnace to the house in the trench. Fill the trench in over top of the plumbing or ductwork. The piping or ductwork should be covered with insulation as it is specific to an outdoor installation.

In the house, run ductwork or plumbing from the location of your old furnace to the location where you will be tying in your new ductwork or plumbing. Connect this junction, making sure that all of your connections are tight and you insulate around the area where the new ductwork or plumbing is to prevent drafts.

If you are using a liquid heating system (oil or water), you should now prime the system by pumping oil or water into the plumbing until you know it is full and free of air pockets. This is accomplished by running the pump (included in the furnace assembly) while liquid is pushed into the pipes. When liquid comes out of the "return" plumbing heading toward the furnace, your system is full.

Start up your furnace and check for leaks by examining all of the connections in the ductwork or plumbing. Turn the fan on if you are using a forced air system and check to see if each register is receiving the same air pressure. If not, adjust the register flaps and internal duct baffles to achieve equal air pressure.